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Stebbing J, Lit LC, Zhang H, Darrington RS, Melaiu O, Rudraraju B, Giamas G. The regulatory roles of phosphatases in cancer. Oncogene 2014; 33:939-53. [PMID: 23503460 DOI: 10.1038/onc.2013.80] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 02/01/2013] [Indexed: 02/06/2023]
Abstract
The relevance of potentially reversible post-translational modifications required for controlling cellular processes in cancer is one of the most thriving arenas of cellular and molecular biology. Any alteration in the balanced equilibrium between kinases and phosphatases may result in development and progression of various diseases, including different types of cancer, though phosphatases are relatively under-studied. Loss of phosphatases such as PTEN (phosphatase and tensin homologue deleted on chromosome 10), a known tumour suppressor, across tumour types lends credence to the development of phosphatidylinositol 3-kinase inhibitors alongside the use of phosphatase expression as a biomarker, though phase 3 trial data are lacking. In this review, we give an updated report on phosphatase dysregulation linked to organ-specific malignancies.
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Affiliation(s)
- J Stebbing
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - L C Lit
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - H Zhang
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - R S Darrington
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - O Melaiu
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - B Rudraraju
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - G Giamas
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
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52
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Ung N, Putoczki TL, Stylli SS, Ng I, Mariadason JM, Chan TA, Zhu HJ, Luwor RB. Anti-EGFR therapeutic efficacy correlates directly with inhibition of STAT3 activity. Cancer Biol Ther 2014; 15:623-32. [PMID: 24556630 DOI: 10.4161/cbt.28179] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Several agents targeting the epidermal growth factor receptor (EGFR) have been FDA-approved to treat cancer patients with varying tumor types including metastatic colorectal cancer. Many patients treated with anti-EGFR therapy however do not respond and those that do initially respond often acquire resistance. Here we show a clear correlation between the efficacy of anti-EGFR inhibitors with their ability to inhibit STAT3 activity in A431 epidermoid carcinoma cells and in a series of wt K-RAS expressing human colon cancer cell lines. Furthermore, the ability of cetuximab to inhibit growth also correlated with its ability to inhibit STAT3 activity in tumor xenograft animal studies. In addition, stable knockdown of the STAT3 phosphatase, protein tyrosine phosphatase receptor delta (PTPRD) resulted in enhanced STAT3 activity and subsequent resistance to cetuximab in DIFI colon carcinoma cells. This resistance could be reversed by STAT3 inhibition. Finally, HN5 cells with acquired resistance to the EGFR tyrosine kinase inhibitor, AG1478 displayed greater STAT3 activity than the HN5 control cell line. These AG1478-refractory HN5 cells were re-sensitized to AG1478, cetuximab and erlotinib when co-treated with a STAT3 inhibitor. Taken together, our current data indicates a key role of STAT3 activity in promoting resistance to anti-EGFR therapy and suggests that anti-EGFR therapy in combination with inhibitors that block STAT3 may provide therapeutic benefit for patients with mCRC and other EGFR driven tumor types.
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Affiliation(s)
- Nelson Ung
- Department of Surgery; The University of Melbourne; The Royal Melbourne Hospital; Parkville, VIC Australia
| | - Tracy L Putoczki
- Department of Surgery; The University of Melbourne; The Royal Melbourne Hospital; Parkville, VIC Australia; Inflammation Division; Walter and Eliza Hall Institute of Medical Research; Parkville, VIC Australia; Department of Medical Biology; The University of Melbourne; Parkville, VIC Australia
| | - Stanley S Stylli
- Department of Surgery; The University of Melbourne; The Royal Melbourne Hospital; Parkville, VIC Australia; Department of Neurosurgery; The Royal Melbourne Hospital; Parkville, VIC Australia
| | - Irvin Ng
- Department of Surgery; The University of Melbourne; The Royal Melbourne Hospital; Parkville, VIC Australia
| | - John M Mariadason
- Ludwig Institute for Cancer Research; Austin Health; Heidelberg, VIC Australia
| | - Timothy A Chan
- Human Oncology and Pathogenesis Program and Department of Radiation Oncology; Memorial Sloan-Kettering Cancer Center; New York, NY USA
| | - Hong-Jian Zhu
- Department of Surgery; The University of Melbourne; The Royal Melbourne Hospital; Parkville, VIC Australia
| | - Rodney B Luwor
- Department of Surgery; The University of Melbourne; The Royal Melbourne Hospital; Parkville, VIC Australia; Department of Medicine; The University of Melbourne; The Royal Melbourne Hospital; Parkville, VIC Australia
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Wang Y, Ren F, Wang Y, Feng Y, Wang D, Jia B, Qiu Y, Wang S, Yu J, Sung JJ, Xu J, Zeps N, Chang Z. CHIP/Stub1 functions as a tumor suppressor and represses NF-κB-mediated signaling in colorectal cancer. Carcinogenesis 2013; 35:983-91. [PMID: 24302614 DOI: 10.1093/carcin/bgt393] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The carboxyl terminus of Hsc70-interacting protein (CHIP, also named Stub1), a U-box containing E3 ubiquitin ligase, is involved in degradation of certain oncogenic proteins. Recent studies indicated that CHIP suppresses tumor progression in human cancers by targeting Src-3, hypoxia inducible factor 1α, NF-κB, ErbB2 and c-Myc. Here, we report that CHIP was downregulated, predominantly, in the late stages of human colorectal cancer (CRC), and that the CHIP promoter was hypermethylated in CRC specimens. Overexpression of CHIP in HCT-116 cells resulted in impaired tumor growth in nude mice and decreased abilities of tumor cell migration and invasion. Conversely, depletion of CHIP in HCT-116 cells promoted tumor growth and increased tumor cell migration and invasion. CHIP was further found to negatively regulate NF-κB signaling in HCT-116 cells by promoting ubiquitination and degradation of p65, a subunit of the NF-κB complex. The suppressive effect of CHIP led to decreased expression of NF-κB-targeted oncogenes including Cyclin D1, c-Myc, MMP-2, VEGF and IL-8. We proposed that CHIP inhibits the malignancy of CRC cells, possibly through targeting NF-κB signaling. This study provides functional evidence for CHIP as a potential tumor suppressor in CRC, and CHIP expression may be a marker for stages of CRC.
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Affiliation(s)
- Yangmeng Wang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Medicine, National Engineering Laboratory for Anti-tumor Therapeutics, Tsinghua University, Beijing 100084, China
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54
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Li R, Hu Z, Sun SY, Chen ZG, Owonikoko TK, Sica GL, Ramalingam SS, Curran WJ, Khuri FR, Deng X. Niclosamide overcomes acquired resistance to erlotinib through suppression of STAT3 in non-small cell lung cancer. Mol Cancer Ther 2013; 12:2200-12. [PMID: 23894143 PMCID: PMC3795834 DOI: 10.1158/1535-7163.mct-13-0095] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The emergence of resistance to EGF receptor (EGFR) inhibitor therapy is a major clinical problem for patients with non-small cell lung cancer (NSCLC). The mechanisms underlying tumor resistance to inhibitors of the kinase activity of EGFR are not fully understood. Here, we found that inhibition of EGFR by erlotinib induces STAT3 phosphorylation at Tyr705 in association with increased Bcl2/Bcl-XL at both mRNA and protein levels in various human lung cancer cells. PTPMeg2 is a physiologic STAT3 phosphatase that can directly dephosphorylate STAT3 at the Tyr705 site. Intriguingly, treatment of cells with erlotinib results in downregulation of PTPMeg2 without activation of STAT3 kinases [i.e., Janus-activated kinase (JAK2) or c-Src], suggesting that erlotinib-enhanced phosphorylation of STAT3 may occur, at least in part, from suppression of PTPMeg2 expression. Because elevated levels of phosphorylated STAT3 (pSTAT3), Bcl2, and Bcl-XL were observed in erlotinib-resistant lung cancer (HCC827/ER) cells as compared with erlotinib-sensitive parental HCC827 cells, we postulate that the erlotinib-activated STAT3/Bcl2/Bcl-XL survival pathway may contribute to acquired resistance to erlotinib. Both blockage of Tyr705 phosphorylation of STAT3 by niclosamide and depletion of STAT3 by RNA interference in HCC827/ER cells reverse erlotinib resistance. Niclosamide in combination with erlotinib potently represses erlotinib-resistant lung cancer xenografts in association with increased apoptosis in tumor tissues, suggesting that niclosamide can restore sensitivity to erlotinib. These findings uncover a novel mechanism of erlotinib resistance and provide a novel approach to overcome resistance by blocking the STAT3/Bcl2/Bcl-XL survival signaling pathway in human lung cancer.
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Affiliation(s)
- Rui Li
- Corresponding Author: Xingming Deng, Division of Cancer Biology, Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, GA 30322.
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Li R, You S, Hu Z, Chen ZG, Sica GL, Khuri FR, Curran WJ, Shin DM, Deng X. Inhibition of STAT3 by niclosamide synergizes with erlotinib against head and neck cancer. PLoS One 2013; 8:e74670. [PMID: 24019973 PMCID: PMC3760825 DOI: 10.1371/journal.pone.0074670] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 08/05/2013] [Indexed: 11/26/2022] Open
Abstract
Epidermal growth factor receptor (EGFR) is extensively expressed in head and neck cancer. However, EGFR-targeted therapy has only modest efficacy in head and neck cancer, through mechanisms that are not fully understood. Here, we found that inhibition of EGFR by erlotinib stimulated phosphorylation and activation of STAT3 leading to increased Bcl2/Bcl-XL expression in head and neck cancer cells, which may dampen the therapeutic efficacy of erlotinib against head and neck cancer. Erlotinib-enhanced STAT3 phosphorylation results, at least in part, from suppression of its physiological phosphatase, PTPMeg2. Specific knockdown of STAT3 by RNA interference significantly sensitized head and neck cancer cells to erlotinib treatment. Pharmacological inhibition of STAT3 by niclosamide not only blocked erlotinib-stimulated STAT3 phosphorylation but also synergistically repressed head and neck cancer growth in vitro and in vivo. Combined inhibition of EGFR and STAT3 by erlotinib and niclosamide more effectively induced apoptosis in tumor tissues without toxicity for normal tissues. Based on our findings, treatment with erlotinib combined with niclosamide may offer an effective therapeutic approach to improve the prognosis of head and neck cancer.
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Affiliation(s)
- Rui Li
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute, Emory University, Atlanta, Georgia, United States of America
| | - Shuo You
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute, Emory University, Atlanta, Georgia, United States of America
| | - Zhongliang Hu
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Emory University, Atlanta, Georgia, United States of America
| | - Zhuo G. Chen
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Emory University, Atlanta, Georgia, United States of America
| | - Gabriel L. Sica
- Department of Pathology, Emory University School of Medicine and Winship Cancer Institute, Emory University, Atlanta, Georgia, United States of America
| | - Fadlo R. Khuri
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Emory University, Atlanta, Georgia, United States of America
| | - Walter J. Curran
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute, Emory University, Atlanta, Georgia, United States of America
| | - Dong M. Shin
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Emory University, Atlanta, Georgia, United States of America
| | - Xingming Deng
- Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute, Emory University, Atlanta, Georgia, United States of America
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56
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Kim NH, Park HJ, Oh MK, Kim IS. Antiproliferative effect of gold(I) compound auranofin through inhibition of STAT3 and telomerase activity in MDA-MB 231 human breast cancer cells. BMB Rep 2013; 46:59-64. [PMID: 23351386 PMCID: PMC4133824 DOI: 10.5483/bmbrep.2013.46.1.123] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Signal transducer and activator of transcription 3 (STAT3) and telomerase are considered attractive targets for anticancer therapy. The in vitro anticancer activity of the gold(I) compound auranofin was investigated using MDA-MB 231 human breast cancer cells, in which STAT3 is constitutively active. In cell culture, auranofin inhibited growth in a dose-dependent manner, and N-acetyl-L-cysteine (NAC), a scavenger of reactive oxygen species (ROS), markedly blocked the effect of auranofin. Incorporation of 5-bromo-2'-deoxyuridine into DNA and anchorage-independent cell growth on soft agar were decreased by auranofin treatment. STAT3 phosphorylation and telomerase activity were also attenuated in cells exposed to auranofin, but NAC pretreatment restored STAT3 phosphorylation and telomerase activity in these cells. These findings indicate that auranofin exerts in vitro antitumor effects in MDA-MB 231 cells and its activity involves inhibition of STAT3 and telomerase. Thus, auranofin shows potential as a novel anticancer drug that targets STAT3 and telomerase.
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Affiliation(s)
- Nam-Hoon Kim
- Department of Medical Lifescience, College of Medicine, The Catholic University of Korea, Seoul, Korea
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57
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Ren F, Su F, Ning H, Wang Y, Geng Y, Feng Y, Wang Y, Zhang Y, Jin Z, Li Y, Jia B, Chang Z. SIPAR negatively regulates STAT3 signaling and inhibits progression of melanoma. Cell Signal 2013; 25:2272-80. [PMID: 23917203 DOI: 10.1016/j.cellsig.2013.07.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 07/08/2013] [Accepted: 07/26/2013] [Indexed: 01/10/2023]
Abstract
Persistently activated STAT3 is important for tumorigenesis in a variety of cancers, including melanoma. Although many co-factors in the regulation of STAT3 activity have been identified, it remains unclear how STAT3 phosphorylation is negatively regulated. Here, we report that SIPAR (STAT3-Interacting Protein As a Repressor) inhibits STAT3 activity by accelerating its dephosphorylation. We observed that SIPAR directly interacted with STAT3 upon IL-6 stimulation. Moreover, over-expression of SIPAR reduced, whereas depletion enhanced, the level of phosphorylated STAT3. We further demonstrated that SIPAR inhibited the growth of melanoma cells by decreasing the level of phosphorylated STAT3 and the expression of its target genes. These results suggest that SIPAR, functioning as a new negative regulator, inhibits STAT3 activity by enhancing its dephosphorylation and represses melanoma progression.
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Affiliation(s)
- Fangli Ren
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Medicine, School of Life Sciences, Tsinghua University, Beijing 100084, China
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58
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Nunes-Xavier CE, Martín-Pérez J, Elson A, Pulido R. Protein tyrosine phosphatases as novel targets in breast cancer therapy. Biochim Biophys Acta Rev Cancer 2013; 1836:211-26. [PMID: 23756181 DOI: 10.1016/j.bbcan.2013.06.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 06/01/2013] [Indexed: 02/07/2023]
Abstract
Breast cancer is linked to hyperactivation of protein tyrosine kinases (PTKs), and recent studies have unveiled that selective tyrosine dephosphorylation by protein tyrosine phosphatases (PTPs) of specific substrates, including PTKs, may activate or inactivate oncogenic pathways in human breast cancer cell growth-related processes. Here, we review the current knowledge on the involvement of PTPs in breast cancer, as major regulators of breast cancer therapy-targeted PTKs, such as HER1/EGFR, HER2/Neu, and Src. The functional interplay between PTKs and PTK-activating or -inactivating PTPs, and its implications in novel breast cancer therapies based on targeting of specific PTPs, are discussed.
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Affiliation(s)
- Caroline E Nunes-Xavier
- BioCruces Health Research Institute, Hospital de Cruces, Plaza Cruces s/n, 48903 Barakaldo, Spain
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59
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Gopalan A, Yu W, Sanders BG, Kline K. Eliminating drug resistant breast cancer stem-like cells with combination of simvastatin and gamma-tocotrienol. Cancer Lett 2013; 328:285-96. [DOI: 10.1016/j.canlet.2012.10.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 09/11/2012] [Accepted: 10/02/2012] [Indexed: 12/26/2022]
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